Process of producing acetylene gas



April 14, 1936. R` G, WULFF 2,037,056

S PROCESS .OF PRODUCING ACETYLENE GAS I Filed May 9, 1951 z sheets-sheetl 1 F/ae 62:5 J g3 41e H54 f5 E aar" April 14, 1936.

R. G.,WULFF PROCESS OF PRODUCING ACETYLENE GAS Filed May 9, 1931 2 Sheets-Sheet 2 ci l Patented Apr. 1.4, 1936 UNITED STATES PRooEss oF PnonUcrNG AcE'rYLENE GAS Robert G. Wulff, Los Angeles, Calif., assigner to Wulff Process Company, Los Angeles, Calif., a corporation of California Application May 9, 1931, Serial No. 536,146

This invention relates to the production of acetylene gas and particularly to a method of producing acetyene gas. 1

This application is a continuation in part of my copending application led January 11, 1927, Serial No. 160,341.

At the present time the only commercial method of making acetylene gas is from calcium carbide. Calcium carbide is a product of lime and carbon which have been caused to react by a high temperature heat. Thecarbide is shipped to the place where the gas is to be generated and is placed in a common form of acetylene gener-v ator. The carbide in the generator is contacted with Water which produces a chemical reaction and releases acetylene gas.

I have found that hydrocarbons, such as natural gas, are capabl of being treated so that acetylene gas C2H2 may be produced. Natural gas is available in large quantities and at a low cost, thus being a favorable raw material from which to obtain acetylene gas.

It is an object of this invention to provide a method of producing acetylene gas from natural gas.

It is a further object of thel invention to provide a process of obtaining acetylene gas from a hydrocarbonaceous gas by passing the gas into contact with a mass of highly heated particles.'

Other objects and advantages of the invention will be made evident hereinafter. J

Referring to the two drawings. in which I illustrate a preferred apparatus of my invention:

Fig. 1 is a vertical view, partly sectioned, diagrammatically showing a complete apparatus.

Fig. 2 is a section taken on the line 2-2 of Fig. 1.

Fig. 3 is a section taken on the liney 3-3 of Fig. 1.

Fig. 4 is an enlarged fragmentary section of the upper end of a precipitator of the invention."

Fig. 5 is a vertical section through a valve constructionof the invention.

Figo is a vertical section through a valve' r construction of a modification of my invention.

Referring particularly to Fig. 1, the invention includes a furnace II which is shown in crosssection in this figure. 'I'he lfurnace, II includes a shell I2 having a cover I3 secured thereto by bolts I4 in air-tight relationship therewith, thus providing an air-tight space within the shell I2. Extended vertically through the shell isla cylindrical tube I5 which is preferably formed from red carborundum. The tube I5 provides a cylindrical treating space indicated by the numeral Il. The lower end of the tube I5rests within a collar I8 and is surrounded by packing I9, which may be asbestos or an equivalent material, which provides a tight seal. 'I'he upper end of the tube I5 extends inside a collar 2| and 5 I is surrounded by packing 22 which forms a tight seal. The purpose of the packing means illustrated is to permit a relative expansion and contraction between the tube I5 and the' shell I2 so that no undue strains will be'placed on either of 10 the parts. At the lower end of the tube I5 is a burner structure 23 which has a sleeve 24 placed on the axis of the tube I5. The sleeve 24 is preferably made from fused silica. Resting on the upper. end of the sleeve 24 is a plate 25 15 having screen openings 26 'formed vertically therethrough. 'Ihe plate 25 is formed from fired carborundum. Surrounding the sleeve 24 is insulation 21 which is preferably silica powder. Placed in the chamber Il are heating, and con- 20 tacting particles 29. The heating and contacting particles 29 are formed from carborundum crystals and are preferably of very small size.

However, particles of any material capable of withstanding the high temperature. can be used, 25 so long as these particles do not harmfully aect or prevent the forming of the acetylene. vAt the lower end of the chamber Il the particles are four mesh or smaller, at the central part of the chamber Il they may be slightly larger, say about 30 three mesh, and at the upper end of the chamber I1 they may be three mesh or slightly smaller. The difference in size of the particles at dierent parts is optional and may be varied according to judgment. The space in the shell I2 surrounding v35 the tube I5 is lled with insulation 3| which is preferably silica powder. The purpose of the silica powder is not only to lessen dissipation of heat, but also to support the tube I5. The silica powder packs around the tube I5.

The bottom of the shell I2, has a nipple which is in communication with the lower end `of the sleeve 24. Secured to the nipple 35 is a tting 36 by means of which a combustible mixture supply line 3l is connected to the cham- 45 ber I1. Attached to` the combustible mixture supply line 3l is a mixer 38 which is of conventional construction. Mixers for gas and air 'are well known in the art, vand-the details therespace 45 formed by a projection 46 and a cover plate 41. Connected to the cover plate 41, so as to communicate with the space 45, is a flue gas-line 48. Connected to the flue gas-line 48, adjacent to the cover plate 41, is a reaction gasline 49. l

Flows of gas through the various gas-lines are controlled by solenoid operated valves. The airline 49 has a valve 5|, the fuelvgas-line 42 has a valve 52, the fiuelgas-line 4 8has a valve 53, and the reaction gas-line 49 has: avalve 54. In a modification of my process I use a valve |49 in the gas-line 49 instead of the valve 54.

The valves 5| to 54 inclusive are typically illustrated in Fig. 5. Referring 4to this gure, the numeral 51 represents a body having a passage 58 formed therethrough to which the pipe rline is connected. Near the central part of the passage 58 is a seat 59 above which is placed a lantern or cage 69. Packing 6| is forced downward against the lantern 69 by means of a. nut or gland 62. n A valve 63 .is adapted to engage the seat 59 and thus'close the passage 58. vA stem 64 of the valve 63 extends upward through the lantern, packing andlgland, and has a thimble 66 secured to the upperend thereof, the

thimble 66 resting in a cavity 61 of thevgland i '62. Compressed between the thimble 66 and the lower part of the gland 62 is a spring 68 which ordinarily holds the valve 63 against the seat 59 so as to close the passage 58. Supported above the construction just mentioned is a solenoid 19 having a solenoid coil 1| and an armature 12 which rests in a central opening 13 of the solenoid coil 1|. The armaturer12 Ais made from iron and has a shaft 15 extending downward into engagement with the thimbl'e .66. When the solenoid is energized, the armature 12 is moved downward into the central part of the solenoid coil 1| and the thimble 66 is depressed. This will force the valve 63 downward from engagement with the seat 59 and open the passage 58.

For the purpose of controlling the operation of the valves I provide a controller 18, diagrammatically illustrated in Fig. l. 18 has a base 19 which supports `bearings 89. Rotatably carried bythe bearings 89 is a main shaft 8| which is rotated by a drive means consisting of a motor 83, a worm 84, and a worm wheel 85, which worm wheel isconnected to the main shaft 8|. Supported by the main shaft 8| is a plurality of disc contacts 81 which are insulated from the shaft as illustrated. Each disc contact has a metallic portion 88`which is at all times engaged by a contact nger 89, and

which is intermittently engaged by a contact iinger 99 as the main shaft `8| is rotated. It should be seen that as each disc rotates, the contact finger 99 `first engages the metallic portion 88 and then an insulation part 92.

The valves and the controller 81 are connected in an electric circuit as follows: A conductor is connected to the motor 83, as' shown, and it is connected to each contact finger 89 by means vof branch conductors 96. Each contact finger 99 is connected to the solenoid coil 1| 'ofv a valve by means of a conductor 98. Each solenoid coil 1| and the motor 83 are connected to a conductor 99.

A precipitator ||0 of my invention isfillustrated in Figs. 1, 3 and 4. The precipitator l ||9 has a metal tank I|| towhich a water-sealed outlet ||2 is connected near-the upper end thereof. The water-sealed outlet ||2 has a U tube The controller portion H3 in which a body of water may co1- lect in order to form a seal. Extended into the tank from a cover ||4 thereof is a steel tube ||6 which forms an outer electrode of the precipitator. Formed at the upper end of the precipitator above the tank and in communication with the upper end of the steel vtube ||6 .is a dome ||1 to which a pipe 8 is connected,

the pipe ||8 being also connectedto the fitting 36. Extended through the dome ||1 into the upper end of the steel tube` ||6 is a protector tube |29 which is preferably made from fused I I6 near the lower end thereof. The steel tube tween the electrodes, a corona around the wire electrode |22 being produced. The lower end of lthe steel tube I6 is provided with a valve in the form of a plate |21 which is centralized by fingers 28 and resiliently retained against the bottom of the tube by coil springs |39. As illustrated best in Fig. 4 a wash fluid ring |3| is retained in the upper end of the steel tube I6. The wash fluid ring |3| surrounds the protector tube |29 and has downward directed openings |32 which direct wash fluid along the interior surface of the steel tube 6. Connected to the wash fluid ring |3| is a pipe |33. Connected to the upper part of the tank Well above the level of a body of wash fluid |34 therein, .is a treated gas delivery line |36 having a solenoid operated valve |31 which is the same construction as any of the valves 5| to 54 inclusive which have already been described. The valve |31 is connected to the controller 18 in the same manner and is operated in the same manner as the other valves.

`The treated gas delivery line may be extended to a gas holder or to an apparatus for recovering acetylene from the treated gas.

In a modification of my process I may provide that the rate lof flow of reaction gas is progressively reduced as the reaction time continues. To this end the valve 54 may be replaced by a valve |49 which is typically illustrated in Fig. 6. This valve is operated by the same electrical controls, but in a slightly modified manner, as will hereinafter be described.

Referring to Fig. 6, 'the numeral |4| represents a body having a passage |42 formed therethrough to which the pipe line is connected. Near the central part of the passage |42 is a valve seat |43. A valve poppet |44 is adapted to engage the valve seat |43 and thus close the passage |42.

r`'I'he valve poppet |44 is connected to an armature '|45 by means of a valve stem |46. 'I'he armature is connected by valve stem |41 .to dash pot piston |48 which is adapted -to move in dash pot |89. 'Ihe dash pot |69 isV completely filled with glycerine orA other suitable nuid on both sides of the piston |48. The dash pot piston 48 is provided with a check valve |49 which is so constructed as to allow the glycerine yto go from the upper dash pot chamber |59 tothe lower dash pot chamber but 4not vice versa. The dash pot is provided with a by-pass |52, between the upper and 'lower chambers of the dash pot. The dash pot piston is also provided with an orice |53. Above the armature |45 is moved upward into the central part of the solenoid coil |58, thereby compressing the spring |54, raising' the valve poppet |44 and opening the passage 42.

The valve is primarily adapted to be used in lieu of valve 54 and the same electrical connections are used. The disc contact 81-which regulates the flow of `current tothe solenoid coill |58 must be changed, however, so that the disc is composed practically entirely of an insulating part 92. This is because of the fact thatA the solenoid coil is to be energized only momentarily. In energizing the solenoid coil |58, the glycerine in the 'upper uash pot chamber |50 is forced through the check valve |49 into the lower chamber |5|. lAs soon as the circuit is broken the valve vpoppet |44 closes very slowly due to the passage of glycerine through the orifice |53 and the action of the spring |54. pot piston reaches the by-pass |52 the valve poppet |44 is suddenly closed to the fully closed position Adue to the action of the spring |54.

'In other words, the valve operates so that the rate of flow throughthe passage |42 is progressively reduced as the cycle continues. The disc contact 81 for this valve is set so that the solenoid coil is energized just before the valve |31 is opened and the spring |54, orifice |53, and by-pass |52 are such that the valve is closed just before the valve |31 is closed.

The method of my invention is as follows:

In starting up the apparatusthe valves 5I, 52 and 53 are open and the valves 54 and |31 are closed. The positions of these different valves are determined by the controller 18. In the drawings the valves 5|, 52, and 53 would be closed since the contact ngers 90 in the circuit of the solenoids of these valves-engage the insulation parts 82 of their respective disc contacts 88. Fig. l, therefore, illustrates the invention at a different period in the operation of the apparatus. The valves 5| and 52, being open, supply air and fuel gas through the pipes 40 and 42 respectively. The air in passing through the heater 4| is raised in temperature. The fuel gas is preferably a natural gas which is`obtained from the same source as the gas from which the acetylene gas is to be made. The proportions of air and fuel gas, which I prefer to use,`are twelve volumes of air to one volume of fuel gas, being the lproportion for complete combustion of the fuel gas used. The gas and the air pass into the mixer 38 where they are thoroughly mixed and where a completely combustible mixture is obtained. The combusti.

ble mixture passes through the combustible mixture supply line 31 and through the burner structure 23 into the chamber |1. The combustible mixture ows upward through the ilue gas-line 48 and is lighted where it issues therefrom. The

flame will burn back into the chamber i1 to a point immediately above the burner structure 23.

When the dash- To prevent the combustible mixture from burning in back of the burner structure 23, the velocity of the combustible mixture may be increased at this time so that the velocity through the sleeve 24 is greater than the burning of the mixture. The burning of the combustible mixture in the chamber I1 heats the heating and contacting particles to a very high temperature and is continued until the maximum temperature in the lower end of the chamber l1 directly above the burner structure 23 is about 3000 F. This tem-I perature is the maximum temperature which it is practical and economical to obtain in the operation of myprocess using natural gas as fuel. The temperature at the upper end of the chamber |1 is considerably lower, since the intensity of the llame is greatest immediately above the burner structure. l

The pressure of the combustible mixture in the fitting 36, when proper operating temperature is attained, is about four pounds per square inch, and it is obvious that a pressure will be applied to the body vof uid |34 in the steel tube I6 of the precipitator |||l which will force the water level downward into a position indicated at |40 in Fig. 1.

The next step is the. treating o'r reaction timev of the process. a timing device moves into the position illustrated in the drawings. The electricircuits to the valves 5|, 52 and 53 are broken and the electric circuits to the valves 54 and |31 are comv pleted. This changes the positions of the valves,

opening the valves 54 and |31 and closing the valves 5| to,53 inclusive. The valves 54 and |31 are kept open during the entire reaction period ofthe process. Instead of using a valve similar to the valve 54, I sometimes prefer to use a valve similar -to the valve |40 shown in Fig. 6 so that the rate of flow. of the reaction gas is progressively reduced as the reaction time continues. 'I'his is in order to provide a rate of reaction gas ilow that is best suited at every instant of the reaction time to the temperature conditions existing'in the furnace. Reaction gas at this time flows through the reaction gas-line 49 and into the chamber |1. The reaction gas in this disclosure of the invention is raw natural gas such as maybe obtained in large quantities in the oil fields of any oil producing locality.

The following is a typical analysis of natural gas obtained from wells in southern California:

CO2 0.72% Carbon dioxide 0:: 1.23% Oxygen CnHzn 1.69% Ethylene and higher homologs N2 0.00% Nitrogen (assumed).

CzHs 15.44% Ethane CH4 80.9% Methane 99.98% Total The reaction gas in entering the chamber |1 comes in contact with the heating and contacting particles 29 and is warmed in the upper end of the chamber. At the central part of the chamber the natural gas becomes hot, and when The controller 18 which acts as 3400 F. just above the burner structure, but in order todo so it takes at least 30 minutes of heating with acorresponding low fuel efficiency.' As set forth on page 3, at the end of the heating period the temperatures I obtain are approximately 3000 F. 'I'he maximum temperature is maintained for only an instant since the temperature drops considerably the moment that the reaction gas starts through. As the reaction period continues the contents of the tube I5 are cooled until the maximum temperature of the tube is approximately 2200 F. The fuel is then turned on and a new cycle commenced. Thus the variation` in temperature of the hottest portion of the tube |5 is from 3000" F. to 2200 F., giving an average temperature vof approximately 2600 F. Obviously, it is the nature of any intermittent process like this to have fluctuating conditions in which the same steps are repeated many times. In view of the progressive drop in reaction temperature during the reaction time, the reaction gas is best passed more and more slowly through the tube I5 as the reaction time progresses, since it takes longer to form acetylene at lower temperatures. Thus, as explained above, the reaction gas valve |40 is automatically and progressively operated to reduce the rate of gas flow during the reaction time. Undoubtedly acetylene forms more eiiiciently during the rst portion of the reaction period, although considerable quantities of acetylene are still being produced just before the. reaction time ends and the fuel time begins. As already set forth, I prefer to heat the tube I5 to a temperature of about 3000 F., and then to allow the reaction period to continue until the maximum temperature of the tube is about 2200 F. Using other natural gases, or raw materials other than natural gas, it probably is preferable to heat the tube to a diiferent maximum temperature and to continue the process until a different lower limit is reached. It may be preferable to make use of a .shorter cycle, for example,` heating the tube until a maximum temperature of about 2800'l F. is obtained and continuing the reaction period until a temperature of about 2300 F. is reached. I have found that acetylene begins to appear at cracking'temperatures of 1800 F., and that the percentage of acetylene formed increasing with the temperature clear up to the temperature limits of furnace combustion. The temperature limits in the tube I5 and the average obtained in the treatment of reaction gas therein, as just given, is for the condition where theair ofthe combustible mixture, that is, the air for the fuel, is not preheated, but is mixed with the fuel gas at room temperature and fed to the burner structure in this condition. If the air is preheated the temperatures in the tube I5 are somewhat higher than the figures given.

The treated gas passes through the burner structure 23 and the pipe ||8 into the upr end of the tube ||6 where it is suddenly chilled by the washing action of the wash fluid and reduced to such a temperature that the acetylene gas becomes stable. The treated gas passes downward through the tube IIS where it is subjected to the action of the electric eld which operates to remove any solid and liquid particles from the gas. The electric field causes the particles carried by the treated gas to move outward into contact with the inner surface of the tube |I6. The solid or liquid particles consist essentially of tar, oil, and carbon. Wash fluid is supplied to the inner surface of the tube IIS,

as previously described. at a rate of about two cubic feet per hour. The wash fluid is preferably water and contains about 9.1 cubic inches alysis of the treated gas is substantially differentfrom the analysis already given of the natural gas from which the treated gas was formed. The following is a typical analysis of the treated gas whiclliaiasses through the treated gas delivery line CO2 0.70% Carbon dioxide -Oz 0.46% Oxygen CnHzn '7.47% Ethylene and homologs Hz 29.65% Hydrogen i CO 1.69% Carbon monoxide CH4 51.20% Methane `Nz 3.91% Nitrogen 02H6 0.00% Ethane C2H2 4.93% Acetylene The recovery of the actylene gas from the treated gas is not a part of this invention and may be recovered in any of the various well known manners. The acetylene gas, for instance, may be recovered by refrigeration under pressure, b y absorption in a solution of cuprouschloride in ammonia which forms a solid copper carbideY from which acetylene can be liberated in pure form by action of a suitable acid or p0- tassium cyanide, or by a selective solution in acetone using suitable pressure and temperature variations.

With the ending of the reaction time of the apparatus" a complete cycle has been performed.

and a new cycle is commenced. The valves change into opposite positions; that is, into the positions rst mentioned. At the changing of the positions of the valves there is a momentary release of pressure. At this time the valve |21 will close the lower end.of the tube IIB and prevent the wash fluid from illling this tube. When the pressure is again established, the fluid level inside the tube ||6 is as illustrated at |40 in Fig. 1. It will be seen that if it were not.for the valve |21 the tube ||6 might fili with uid to the same level as in the space around the tube IIB in the tank This would result in a shorting of the tube IIB and the wire electrode |22. If the wash fluid were permitted to fill' the tube I6, it would be forced down when the combustible mixture pressure is again established, thus allowing combustible mixture to enter the tube |I6 and mix with the treated gas. As it is, the Water level |40 is below the upper end of the bar insulator |24. When the combustible mixture passes into the lower end of the chamber I1 it is immediately ignited and the carbon de- -posited in aA previous operation is burned, and

the heat value thereof is utilized. For this reason it is desirable to have a small excess of air in the combustible mixture so that the carbon will be effectively burned out.

I'n the normal operation of the apparatus the acetylene gas yield varies between four and six flow and the time length of the fuel time and' the reaction. time. In the tests in which the following data was obtained, the rate of gas iiow during the reaction time was held constant, and was not progressively reduced as the acetylene formation continued. In other yWords a valve similar to the valve 54 was used to regulate the flow of raw materiaLand not a valve similar to the valve I 40. The data gives a number of different tests carried out under different conditions.

Table Test. Air Ges Fuel l'g' Fuel Cycle /Increase No. flow flow flow time time time ratio 214 240 300 2o 4.00l 9. 52" 14.18" 1.283 zu 240 240 20 5.29` 14.29 22.58 1.360 201 300 360 25 7.43 15.15 22.58 1.354 200 300 300 25 5.99 10.59 22.58 1. 515

Time Timeanyparv r t* ticularmole- CH 'rest "gases lig cula in pmj Fuel No. in tube ifagertllieln cent C2H2 15 zone- 214 0.087 f 0.010V 5.06 2.09 234 0.109 .0.0125 5.03 aio 201 0.072 0.0053 4.78 2.19 250 0.072 0.0083 5.00 2.12

through once. In other Words it is that portion of the cycle time in seconds during which the valves are set to allow the vflow of reaction gas and prevent the ow of fuel gas.

4. Fuel time means the number of seconds required for firing the furnace once. In other words-it is that portion of the cycle time in seconds during which the valves are set to allow the flow of fuel gas and prevent the flow ofA reaction gas.

5. Time ratio is proportion of `heating time towreaction-itlme. l

6. Increase ratio is ratio of treated reaction gas-volume (including acetylene) to volume of gas run through (raw reaction gas). This gas on cracking undergoes permanent increase in volume.

tion time plus one fuel time equals one cycle time, as may be seen by adding the figures in the table.

gas is in tube I5, which is an estimate of the actual time in seconds that any one portion of reaction gas is in the tube, for it should be clear that the time requiredfor such a portion of gas to traverse the tube I5 depends on the size of the tube and on how it is filled. A very small tube would require the smallest fraction of time for the gas to get through, whereas a large one might require seconds.

'I'he following illustration will make this period' of time definitely understandable. In my experiments in which I used the apparatus of Fig. 1 and obtained the data of tests Nos. 214, 234, 261, and 266, as givenin the table on page 5, the tube I5 that I used was made from fired carborundum,

measured 27 inches in length, and was 2.0 inches inside diameter. It was fully filled with approximately three mesh carborundum crystals, and I ascertained-that the void space within said tube, where the gas was to flow, was half of the internal volume of the tube without the filling. The net void space thus figured geometrically, is 42.5 cubic inches, or 0.0246 cubic feet. Now in test 214, as set forth in the table referred to, the reaction gas, duringthe reaction time, was flowing at a rate of 300 cubic feet per hour. In other Words, during the 4.66 seconds thatit flowed it was flowing at the rate of 0.833 cubic feet per second. If the void space in the tube was only 0.0246 cubic feet, as figured above, the gas Icould not possibly stay in said tube even one second. The maximum average time it could stay there is 0.0246/0.833 or 0.296 second. It is clear, however, that the reaction gas as it enters the furnace does not stay cold, but immediately begins to expand enormously due to the heat, and is driven through The. fuel time, reaction time and cycle f time are entirely distinct from the time reaction the tube much faster than just calculated. If l the reaction gas reaches a. temperature of 2600 F. in the hottest portion of the tube, We may assume roughly that the temperature averages half way from that to room temperature, or an averageof 1335 F. -By Charles Law for the expansion of gases, we correct the value of 0.296 second to 0.087 second. This last value is the approximate length of time required for any one molecule of the reaction gas to get from the upper end of tube I5 to the lower end under the conditions in which Test No. 214 was performed. I have found, however, that the acetylene formation does not begin at the top of the tube I5. but only near the'bottom Where it is above 1800 F. Obviously the acetylene formation zone decreases in length and volume as the formation of the acetylene continues, due to the cooling oi' said zone bythe reaction gas flowing through. As mentioned on page 3, I have provided means for decreasing gradually the reaction gas ow to allow sufficient time during the reaction time for the acetylene to form efficiently while said acetylene forming zone is decreasing due to drop in temperatures. During the middle of the acetylene forming part of the cycle when the maximum temperature inthe tube I5 is about 2600 F., I have found that the time in seconds in which any particular molecule of the reaction gas is subjected to temperatures great enough to form acetylene gas is about .01 second. This is for the conditions under which Test No. 214 was performed. The remaining tests show corresponding values, since the tube I5 and all other conditions except those noted' in the table were the same. These values have been computed and are set forth in said table.

In general, we prefer to control the flow of the reaction gas so that it is in the tube I from about .07 to. .11 second, as shown in the table. However in using tubes of large capacity or in processes in which the reaction gas is subjected to comparatively .low acetylene forming temperatures, the reaction gas may be in the tube I5 as long as one second. On the othery hand, when tubes of very small capacity are used, or in processes when the reaction gas is subjected to temperatures above 3000 F., the reaction gas vmay be in the tube I5 for about .01 second only.

Similarly in processes when large tubes or comparatively low temperatures are used, the reaction gas may be in the acetylene forming zone for about .1 second, and when narrow tubes or' zone and therefore it takes the gas less than .02

second to traverse this distance. It is advisable also, in large installations, to water jacket the tube IIB wherever possible to chillquickly, and

even to introduce water spray therein just below the burner structure. In general it is desirable to design a furnace so that the reaction gases are cooled as quickly as possible after they leave the acetylene forming zone.

I have found that it is possible to obtain a higher temperature in the chamber I1 by preheating the air and I therefore utilize the air heater 4 I. It is probable that the yield of acetylene gas may be increased by decreasing the size of the carborundum particles 29 so that a larger area of contact may be procured.

The data of the table were secured without preheating the air in order to determine what can be done under these conditions. If the air is preheated and the reaction time is kept the same, the temperatures within the tube I5 are necessarily higher, and the yield of acetylene therefore greater.

The data of the table are merely representative, and do not show the limits within whichi; the process is operable. I have been able, for' instance, to get 5.8% acetylene with a gas flolr at the rate of 14o cubic feet per, hour and a fuel now of 20 cubic feet per hour. The data of said table show conditions where the best results are to be the fuel time, or one-third as long. The acetylene formation period for any particular hydroriation from said conditions will result in loss of emciency. 'I'he last column of the table gives the"cubic feet of fuel required to produce one cubic foot of pure acetylene. Thevalue of 2.0 is about the lowest that I have been able to obtain, while if other conditions are used the value easily goes up to 4.0 and even up to 9.0 and above if the conditions of operation are not properly chosen.

It should be apparent that considerable economy is effected in the invention due to the direct manufacture of the acetylene gas as distinguished from the ordinary method of obtaining the acetylene gas from a previously mentioned carbide.

The. direct manufacture of. the acetylene gas reduces the energy input and eliminates lime losses. The treated gas after the acetylene gas has been separated from it may be sold and there will be no loss in this respect. Economy is effected by using the heat value of the carbon deposited in.

' I can usea natural gas containing large quantities of ethane, propane, and butane, which latter are not -regarded primarily as gasolines. I have found that I can make acetylene from still-vent gases, of the usual gasoline cracking plants, such gases containing high percentages of olefines, particularly ethylene and propylene, together with methane and hydrogen. I regard the hydrocarbons in such cracked gases and vapors very valuable in formation of acetylene. Any such composition as described above is referred to herein as a hydrocarbonaceous gas or a reaction gas. I have also found that in using a reaction gas containing a substantial proportion of paraffin hydrocarbons higher than methane, larger yields of acetylene are obtainable than in using ordinary natural gas as the reaction gas,y 'Ihe words "higher than methane are intended to include gases having a higher proportion lof carbon to hydrogen atoms than methane. Methane CH4 has one carbon atom to four hydrogen or the carbon to hydrogen proportion is 0.25. Ethane Cali/e for example has the higher proportion of .33 3. Y`

The apparatus by which the method may be carried on is of simple construction, being inexpensive to construct and inexpensive in upkeep. 'Ihe method may be carried out at substantially atmospheric pressure.

'I'he surface combustion method of heating the carborundum crystals 29 is highly desirablebecause it avoids the problem of heat transfer through the walls of the chamber I1. 'I'his conduces to an economy in fuel consumption and also to an economy of fuel'time (the time required for heating the particles 29). ,9A further. advantage of surface combustion is that it is possible to offer the maximum temperature where it is needed; that is, inside the chamber I'I and lnot around the walls thereof. f

'I'he use of carborundum for the tube I 5 and the particles 29 is important to the invention. There are many materials which are suitable in ordinary furnaces but cannot be used in my invention either because they destroy the acetylene when formed or cannotstand the high variable temperatures.

Considering the high speed and the pressure with 4which the cold reaction gas is forced down- The carborundum material I have used stands it,

, though if the tubes are not of the best quality of iired carborundum they will crack. It is significant to have found that there is a refractory material that will serve, since the temperatures are so high that no metallic material whatever Would be practical. Not only are the temperatures excessive for metallic surfaces, but the severe oxidation effects during ring, coupled with carbonization and embrittlement during the formation of acetylene, are too severe for anything except stable refractory walls.

The precipitator is an important part of the invention since it serves the purpose of chilling the treated gas to such a temperature at which the acetylene gas is stable and also of removing solid o r liquid particles from the treated gas.

Although I have described my invention with respect to certain particular embodiments thereof, nevertheless I do not desire to be limited to the particular details shown and described ex- Vcept as clearly specified in the appended claims,

since many changes, modications and substitutions may be made without departing from my invention in its broader aspects and my inven- Y tion in its broader aspects may be found useful in many other applications thereof.

I claim as my invention: i 1

1. A process of producing acetylene gas from natural gas comprising: heating refractory particles in excess of 1800 F., passing natural gas into contact with said heated particles for 'a sufficiently brief period to enable acetylene gas to be formed without entirely converting the hydrocarbons into hydrogen Aand carbon, decreasing the ow of said natural gas as said acetylene is formed, and cooling'the resulting gas in less than one second.

2. A process of producing acetylene gas from natural gas comprising: heating refractory particles in a heating chamber in excess of 1800 F., passing natural gas into contact with said heated particles for a sufliciently brief period to enable acetylene gas to be formed without entirely converting the hydrocarbons into hydrogen and carbon, the total time that any particular molecule of said natural gas is in said chamber being less than one second, decreasing the flow ofsaid natural gas as said acetylene is formed, and suddenly cooling the reaction products to a temperature at which acetylene is stable.

3. A process of producing acetylene gase'from natural gas comprising: particles in a heatingchamber in excess of 1800 F., passing natural gas into contact with said heated particles for a sufliclently brief period to enable acetylene gas to be formed without entirely. converting the hydrocarbons into hydrogen and carbon, the total time that any particular molecule of said natural gas is in said chamber being less than` one second, decreasing the flow of said natural gas as said acetylene is formed, and cooling the resulting gas in lesal 'heating refractory 

